Samenvatting:Acetals are considered as an important bio-based diesel additives. Generally, the catalytic production of these compounds from an alcohol and an aldehyde suffers from a low conversion because of thermodynamic limitations. These limitations can be overcome through the in situ removal of the by-product water using, for example, a water selective membrane. A critical evaluation on the membrane performance, catalyst activity, optimal configuration, and feed composition leads to the conclusion that a combined reaction and separation is unlikely to be advantageous. The water permeance of the selected membrane was assessed to be too low in relation with the catalyst activity.